Terminal assembly



Feb. 28, 1961 G, H HANSEN 2,973,503

TERMINAL ASSEMBLY Filed May 9, 1958 TERMINAL ASSEMBLY Gilbert H. Hansen,deceased, late of Batavia, Ill., by Helen R. Hansen, administratrix,Batavia, Ill., assignor to Furnas Electric Company, a corporation ofDelaware vFiled May 9, 1958, Ser. No. 734,368

3 Claims. (Cl. 339-198) sets of contacts which are closed by a iiuidactuatedk stirrup and opened by an adjustable helical main spring. Inorder to make an electrical connection to one of the terminals of theswitch unit of this patent it is necessary `to clean and loop an end ofthe wire to be connected,

and after removing the terminal screw completely, the removed screw isplaced through the loop and the parts are then reassembled. To make aconnection to terminal structure embodying the improvements of theinvention it is only necessary to insert the cleaned end of the wireunder the loosened saddle-shaped pressure plate and by retightening theholding screw the connection is cornpleted.

Accordingly -an object is to provide new and novel improvements in theterminal structures of an electric switch, which will be simple indesign, economical to manufacture, and which will materially simplifythe operation of connecting wires to the said terminal structures.

Another object is to provide an electric switch terminal board whichwill embody improvements in the terminal Y inserts so that the insertsupon being molded in the plastic board will be operatively held andlocked in position.

Another object resides in providing terminal structure for an electricswitch which will employ saddle-shaped pressure plates whereby theinsertion of a wire to be connected is not only materially simplifiedbut the physical gripping of the wire and also the electrical contactbetween the parts is greatly improved.

A still further object is to provide terminal structure for an electricswitch characterized by a board of molded insulating material havingchannels for receiving the side skirts of the saddle-shaped pressurepla-tes, and wherein said board is also provided with sloping aprons forcertain of the terminal structures whereby to facilitate wire insertion.

With these and other objects in view, the invention may consist ofcertain novel features of construction and operation as will be morefully described and particularly pointed out in the specification,drawings and claims appended thereto.

In the drawings which illustrate an embodiment of the invention andwherein like reference characters are used to designate like parts-Figure l is a top plan view showing the terminal board of an electricswitch and which embodies terminal structure coming within theinvention;

'Figure 2 is a longitudinal sectional view taken substantially alongline 2-2 of Figure l;

Figure 3 is a transverse sectional view taken centrally ice .the rearterminal structures substantially along line 44 of Figure 1; and

Figure 5 is an elevational view showing in separated relation theseveral elements going to make up one of the 4terminal structures of theinvention.

Referring tothe drawings, the improved terminal board 1i) for anelectric switch, such as the fluid pressure actuated switch of PatentNo. 2,790, 870, is formed of insulating material and the board has acentral bore 11 extending into the top wall 12, the said borecommunicating with the central opening 13 in the top wall. The wall 1'4is located at the rear end of the terminal board, being integraltherewith, and also integral with the intermediate or terminalsupporting wall 15. A transverse wall 16 is located adjacent the frontend of the board and the same projects upwardly a short distance abovewall 15. The said transverse wall 16 and the terminal supporting wall 15are further characterized by a pair of forwardly extending walls 17 and18. Side wall portions, such as 20 and 21, complete the body portion ofthe terminal board and it will be noted that said last mentionedportions are likewise integral with the several walls of the board sothat the terminal board, sometimes called a terminal block, consists of-a unitary member molded of insulating material and which is equippedwith several wire connecting devices embodying the improvements of theinvention.

iFigure l illustrates a preferred manner of locating four wireconnecting devices on the terminal board 10 and wherein each of saiddevices, as best shown in Figure 5, will include a terminal insert rivet24, a saddle-shaped pressure plate 25, and a holding screw 26. Theterminal insert for each of the wire connecting devices is provided witha head 27 and a cylindrical body portion 28 which is threaded internallyat 29 and knurled externally at 30. Each pressure plate is formed withdepending side skirts 31 and with a front upwardly directed ange 32. Thetop wall 33 of the pressure plates is Iprovided with a projecting rib 34which extends transversely thereof and which forms a holding andgripping element on the underside of the plate for contact with the wireto be electrically connected to the terminal structure. The holdingscrew 26 is conventional in structure and consists of a slotted head 36having an exteriorly threaded shank 37. The terminal inserts are moldedin place in the terminal supporting wall 15 of the board and theknurling 30 on the cylinder body portion of each insert is spirally orangularly disposed so as to improve the .holding and locking of theinserts in the molded plastic. The front flange 32 and the side skirts31 of the pressure plates facilitate the insertion of the wire to beconnected to the terminal, and upon screwing in of the holding screw 26the said wire is gripped and securely held by the projecting rib 34.This gripping action of the projecting rib results from the bite whichthe projecting rib has with the wire to be connected to the terminal.Accordingly, an additional advantage of the projecting rib is that theymaterially improve the electrical contact between the wire and thepressure plate.

Referring to Figures l, 3 and 4, it will be understood that a pair ofwire connecting devices is located forwardly of the transverse wall 16and a second pair of'said devices is located forwardly of the rear wall14. In order to distinguish between the front and rear terminalstructure the inserts for the rear structure, which are connected to thepower line, will be identified by numeral 40, the pressure plates bynumeral 41, and the holding screws by numeral 42. For the front terminalstructures, which are connected to the motor, numeral 44 identities theinserts, 4S the pressure plates, and 46 the holding screws. In Figure lit wil be noted that one pressure plate and a holding screw therefor ofeach pair of terminal structures has been removed to better illustrateVthe insert head and the details of the recesses formed in the topsurface of the wall 15 of the terminal board. This structure will now bedescribed.

The top surface of the terminal supporting wall 1S is formed with arecess for each of the terminal structures, the recesses for the rearstructures being identified'by 50 and 51 and the recess for the frontstructure by numerals 52 and 53. Each recess is substantiallyrectangular in outline and whereas the rear recesses have wall 14,defining their rear limit, the front recesses are similar by reason ofthe transverse wall 16.

The rear recesses are additionally characterized by the spaced sidewalls 54, the .inside wall being formed by the portion 55, and inaccordance with the invention the entrance to each rear recess consistsof a sloping apron 56 and a pad 57, the latter element having a heightequal to that of the terminal insert and said pad also has contact withthe head of the insert for a portion of its periphery. In fact, thesloping apron and pad are produced by the molding operation, at whichtime the inserts are molded in place, and it will be ob served that thehead of a terminal insert is located approximately centrally within`each recess. One of the side walls 58 for each of the front recesses isformed by one of the vertically extending Walls, either 17 or 18, andalso the head of each terminal insert is associated with a pad 59. Sincethe head of a terminal insert has location in each of the recesses, thesaid head in conjunction with the pad forms a three-sided channel, twosides of which accommodate the side skirts of a pressure plate when thesame is operatively associated with the terminal insert.

For making a connection to the old type of terminal it was necessary toclean and loop the wire, and upon complete removal of the terminal screwand insertion of the same through the loop, the parts could then bereassembled. In order to make a connection to one of the terminalstructures, as herein disclosed `and described, it is only necessary toclean the end of the wire and insert the same under a saddle-shapedpressure plate which has been previously loosened for the purpose ofreceiving the wire. Upon retightening the holding screw the connectionis completed. Insertion of the wire uider the pressure plate isfacilitated by the pads and the operation of inserting the wire isadditionally facilitated rby the sloping aprons 56 which lead to ltherear recesses. The pressure plates materially facilitate the op erationof electrically connecting the wire to the terminal structure since byreason of the plates the connection to the wire is practicallyautomatic. The depending side skirts of each pressure plate function torestrict the inserted end of the wire so that it is readily associatedwith and placed in contact with the head of a terminal insert. Thedepending side skirts are able to restrict and confine the inserted endof the wire. since they depend from opposite sides of the plate and havelocation on respective sides of an insert head. The side channelsaccommodate the spaced skirts of a pressure plate so as to uniquelyassociate the plate with the head of a terminal insert and in a mannerto simplify the terminal structure and the operation of connecting awire while improving the physical and electrical connection effected bythe parts.

The invention is not to be limited to or by details of construction ofthe particular embodiment thereof illustrated in the drawings, asvarious other forms of the device will of course be apparent to thoseskilled in the art without departing from the spirit of the invention orthe scope of the claims.

What is claimed is: i Y i l. In a device of the character described, amember of insulating material having an approximately rectangular recessin the top surface thereof, a terminal insert molded in the member andhaving a head portion located within the recess centrally thereof, theheight of the head portion being less than the depth of the recess andsaid terminal insert having a threaded bore extending from the headportion for the major 'length of the insert, a pressure platesubstantially saddle-shaped in transverse section to provide dependingside skirts for location in t-he recess, said depending side skirtsbeing spaced from each other a greater distance than the diameter of thehead portion of the insert but less than the width of the recess, aholding screw adapted to pass through an opening in the top wall of thepressure plate for threaded relation with the threaded bore of theterminal insert to secure the pressure plate to the head portion, andsaid member having a pad formed at the entrance end of the recessproviding a top surface aligned with that o f the head portion andhaving contact with the head` portion, said pad having-a width whichdoes not exceed the diameter of the head portion of the terminal insert.

2. In a device of the character described, a terminal board ofinsulating material having an approximately rectangular recess in thetop surface thereof, terminal structure located in the recess andincluding a terminal insert having a cylindrical body portion molded inthe board and having an enlarged head positioned centrally of therecess, whereby channels are formed on at least two sides of the recess,a pressure plate for location in alignment over the enlarged head, saidpressure plate having side skirts adapted to occupy the channels whenthe plate is operatively associated with the head, a holding screwextending through an opening in the top Wall of the pressure plate andadapted to have-threaded relation with the enlarged head of the insert,whereby to secure the pressure plate to said insert, and said terminalboard having a sloping apron and a pad formed in its top surface inassociated relation with the entrance end of the recess so as tofacilitate the insertion ofV a wire to be connected to the terminalstructure, said pad having a width which does not exceed the diameter ofthe head portion of the terminal insert.

3. A device of the character as defined by claim 2, wherein the slopingapron slopes towards the head of the terminal insert and terminates insaid pad, and wherein the pad has contact with the head and provides atop surface in alignment with that of the head.

References Cited in the le of this patent UNITED STATES PATENTS1,247,916 Weiss Nov. 27, 1917 2,190,363 Knapp Feb. 13, 1940 2,387,630Weakley Oct. 23, 1945 2,425,608 Field Aug. 12, 1947 2,679,634 Rawley May25, 1954 2,701,870 Obszarny Feb. 8, 1955 2,712,123 Wibell et al. June28, 1955 2,855,579 Wintriss Oct. 7, 1958

